Although the rates of serious surgical site infections (SSIs) following outpatient surgery are low, the number of patients who develop these serious infections is substantial and warrants continued quality improvement efforts because outpatient surgery is so common, according to a new study published in the February 19 issue of the Journal of the American Medical Association and funded by the Agency for Healthcare Research and Quality (AHRQ).

Nearly two-thirds of all surgeries in the United States are performed in ambulatory (also known as outpatient) settings that do not include overnight hospital stays. Ambulatory surgeries are usually low- to moderate-risk procedures that are performed on patients who are at lower risk for complications.

In the study, "Surgical Site Infections Following Ambulatory Procedures," researchers used AHRQ's Healthcare Cost and Utilization Project databases to analyze SSI rates following surgery in hospital-owned ambulatory (outpatient) settings in eight states. SSIs are among the most common type of healthcare-associated infection (HAI). The authors found that 877 patients in the eight states, or a rate of just over 3 (3.09) of every 1,000 patients, who had ambulatory surgery were treated within 14 days for a SSI that required hospitalization. At 30 days, the rate increased to nearly 5 (4.84) of every 1,000 patients. These data did not include procedures performed in physicians' offices or freestanding facilities not owned by hospitals.

"Healthcare-associated infections remain a common complication of care following ambulatory surgery," said AHRQ Director Richard Kronick, Ph.D. "The number of patients experiencing these serious infections is an important consideration, and work should continue to make outpatient surgery safer."

AHRQ has undertaken a Safety Program for Ambulatory Surgery, which is promoting the use of the Comprehensive Unit-based Safety Program, a proven method for preventing HAIs, to reduce SSIs and other complications from surgery in ambulatory surgery centers and hospital outpatient departments.

Other studies focused on inpatient hospitalizations have shown that for patients undergoing surgery in the hospital, SSIs are known to be a common complication of care. Approximately 3 percent of hospitalized patients who contract an SSI die from it. Having an SSI can add 7 to 10 days to a hospital stay and add up to $27,600 to the cost of hospital care. Yet, relatively little is known about SSIs in relation to ambulatory surgery.

To address this gap in knowledge, researchers led by Pamela L. Owens, Ph.D., and Claudia A. Steiner, M.D., M.P.H., both of AHRQ, analyzed records of nearly 285,000 ambulatory surgeries (general surgery, orthopedic, neurosurgical, gynecologic, and urologic) that were followed by a serious SSI requiring a hospital stay or an ambulatory surgery visit in adult, low surgical risk patients. The records were from surgeries performed in California, Florida, Georgia, Hawaii, Missouri, Nebraska, New York, and Tennessee in 2010. Given that the study represented 33 percent of the U.S. population, substantially more patients nationwide could experience an infection related to their outpatient surgery.

Because the study found that most of the serious SSIs occur within 14 days, the study's authors recommended that more attention be paid to preventing and reducing infections in the early window following an ambulatory surgery. For example, routine clinical follow-up within 14 days following an ambulatory surgery may help detect infections earlier before they become serious and require hospitalization. "Earlier access to a clinician or member of the surgical team... may help identify and treat these infections early and reduce overall morbidity," the authors wrote.

To date, much of the focus on preventing SSIs and other HAIs has been placed on surgeries that occur during inpatient stays. The study's authors said that the findings from this research reaffirm that HAIs can also occur following outpatient surgeries and that quality improvement programs should also be targeted to prevent infections following ambulatory surgery.

AHRQ and other federal agencies are tackling HAIs under the umbrella of HHS's National Action Plan to Prevent Healthcare-Associated Infections: Roadmap to Elimination. Phase 2 of the Action Plan calls for expanded efforts in outpatient settings, including ambulatory surgery. To support the Action Plan goals, AHRQ has undertaken a variety of projects, including the Safety Program for Ambulatory Surgery, that are applying evidence-based methods for reducing HAIs. Preventing HAIs is a top priority for AHRQ, which has developed numerous tools to combat HAIs such as the Comprehensive Unit-based Safety Program, or CUSP. For more information, please visit www.ahrq.gov.